Telephone-exchange system



2 Sheets-Sheet 1 R. w. vi-IARPER TELEPHONE EXCHANGE SYSTEM Flled July 2 1923 Sept. l5, 1925.

sept. 15, 1925.

R. w. HARPER TELEPHONE EXGHANGE SYSTEM Filed July 2. 1923 2 Sheets-Sheet 2 Patented Sept. 15, 1925.

UNITED STATES-1f ROBERT 1W: HARPER; ori-EAST #OnaNGE,1 NEW- JERSEY; A'ssIGN'OR To WESTERN ELEO- 'rnro COMPANY,Y INCORPORATED, otr-iNEWlYOR-KaNi Yi. ALOORPO'RATION OF NEW- YORK.

Applivers-on med Juiya To all whom t may concern:

Be it known that I, lROBERT 'W1 HARPER, ay citizen? of the United States' of America, residing at East Orange, Yin the county of Essex" and?v State of'NeWl Jersey, have invented certain new andk useful Improvements in Telephone-Exchange Systems, of which thefollowing'is afull, clear, concise,- and exact description.

Thisv invention relates to`telephone exi' change systems, andt particularly toUy those systems whereinA mechanical switching apparatus is employedcin theestablishment of talkingsconnections.

In exchange areas including `both *manual Offices andv automatic" oflicesg Where provision is made forV the extension of callsvv made'in a :manual roiiicefto any ofthe outlying automatic offices,V it found desirable in somefc'asesto have the selective switches in the called automatic office controlled from the mechanism-located at the calling manual oflice.v Bytthisplan the operator Who first-answers therjcall is'enabled to establishfthe interoffice connection which leads to a distant mechanical office Without assistance, the entire. operation offt-her'switches at the distant O'fice being governed by mech-- anismat the originating'ofiicecontrolled'by the answering operator therein.

At the manual oiii'ce a pluralityfof foper` ators positions is `pr`ovided,=each ofl which has access to apluralityof groups of trunks; Vone group leading to eachofthedistant'au-- tomatic offices served. Each position is fur-v ther equipped with a sender controlling-key;

board aset of Ofiic'e keys anda set of indi- (rating lamps for trunk identification. There is also located at the `manual officea group,` of register senders 'commonto the'usefof all" operators,` serving vto` control the Amovement:y

of the switchesin distant'ofiices.' In'order that an idlesender maybe taken foi'use'toVVV extend a Vcall andto associate such sender' with the keyboard at the` operators position'v concerned,'and also lWith an idle'tr'unkinthe particular group leading-.to lthe -desiredJautomatic office, a plurality of switching units is employed.

TELEPHONELEXoH-ANGE"SYSTEM:

M.-Allen, October 28,1924.' In order, hovv-ir Y ever, ltl1`at-the: operatorsvl of .any group,- of positions may not" monopolize y allotted switching units las'fast as they become/allot; ted'l forluse; it 'is 'desirable to :providesome means for giving the operators positions inf'the several;v groups equal preferencerin thefguse' of allotted.I units.V

TheY objectv ofl the invention is,l therefore, to renderwallotted, switching units equally accessible'toiv operators positions of all groups of positions; n f This object isfattained-'by'providing as a v'feature'of -theinvention a group-selector i svvijtchiy associa-ted- Withi the switching unit a'llotter,y which is operated upon fthe initia` tion foffaca'll by, an' operatorfin any group to rselect the grouplinfwhich suchoperators position fisylocated; I

A further feature of the invention resides in the-arrangement ofy such group selector Wherebyif calls are simultaneously initiated inatWo Ormore'groups of positions, an allotted switching Iunit Will `become available for theuse ofthe/operator in the group of positions nearest to the positionfthe group selectoroccupies atzthe instant such calls are initialtedL4 Since-athe'group selector has no definite' nor-mal position, Vthe lorder of preference of -thefgro'ups'of :positions in the use of-'allottejd units-isf'thusmadevariable to give requal;preference to .all groups of positionsfas -tothe number' of'allotted Vunits availa-blefor the use-of e'ach'groupof posi-J tions. f Y

These andother features of'theA invention will bem'ore obviouszvfromfa lconsideration of the description'-givenchereinafter 4andof the'fapp'ended claims;

The accompanyingy drawings ldisclose one embodiment'of the invention as .applied to circuits of the character disclosed in the aforementioned patent to L. M. Allen.

Fig. 1 shows an allotting mechanism, the group selector of the present invention and the starting circuits of two groups of operators positions for allotting idle switching units, portions of which are disclosed yin Fig. 2, for the use of a calling operator.

This ligure corresponds to Fig. 8 of the aforesaid application, having additionally the group selector forming the basis of the present invention. Fig. 2 shows in the right hand portion thereof oiiice keys and associated relays of an operators position in each of two groups of positions; and in the left hand portion thereof two 'of the operators position selector switches of one switching unit and certain of the control relays of such switching unit. The apparatus of Fig. 2 is identica-l with similar apparatus disclosed in Figs. 5 and 6 of the aforesaid application. i

For a complete description ofthe detail construction, relationship and operation of the apparatus disclosed herein, reference y may be had to the aforesaid application. To

enable a better understanding of the present invention a detailed explanation will now be given with respect to its mode of operation.

It will first be assumed that the allotter is standing in such a position as to allot the switching unit, portions of which are shown in Fig. 2, for the use of the operator in any of the five groups of positions who irst initiates a call, that the brushes of the group selector 150 are at the time standing upon the No. 1 terminals of their' associated banks and that an operator whose position is thelirst in group 5, indicated at the right of F ig.'2, initiatesa call in response to the request of a calling subscriber for a connection to an automatic office, represented by office key 251.

The operator in response to the request of the calling subscriber depresses the office key 251 corresponding to the desired oliice, whereupon relays 252 and 253 operate in a circuit (shown in part) extending from battery at the armature and back contact of relay 254, through the right Ywindings of relays 252 and 253, and a contact 'of the depressed oiiice key. .As soon as relay 252 becomes energized, a circuit is closed from battery through resistance 256, the outer contact of rela-y 255, the outer left armature and contact of relay 252, conductor 122, thence to a point between the lower winding of the balancing coil 113 and the windings of polarized relay 115. The iiow of current to ground through the coil 113 and through the windings of polarized relay 115 is in such a. direction as to cause said relay to attract lits armature. Relay 115 closes .a .circuit from battery7 .through the right winding of relay 110, whereupon relay 110 energizes and locks over a circuit extending from battery, through its left winding, inner left arma-ture and contact to ground at the outer left armature and back contact of relay 108.

Relay 110 also establishes an operating circuit for the magnet 151 of group selector 150, which may be traced from battery, through the winding and armature contacts of magnet 151, the outer left armature and front contact of relay 110, brush 152 of selector to ground on the bank terminal on which it is standing. Magnet 151 energizes, interrupting its own operating circuit and advancing the brushes 152, 153, 154, 155, 156 and 157 one step. Brush 152 now engages terminal,158, whereupon a circuit is again established for magnet 151, extending as previously traced to the brush 152, terminal 158, the inner right armature and back Contact of relay 109, conductor 124 to ground at the outer right armature and contact of relay 108. Magnet 151 again energizes, interrupting its own circuit and advancing the brushes of switch 150 a second step. Similarly, as the brush 152 engages terminals 159, 160 and 161, the stepping magnet 151 energizes, advancing the brushes of switch 150. lhen the brush 152 engages terminal 162 there is no effective energizing circuit for magnet 151, since with relay 110 energized, the circuit extending from terminal 162 through the inner right armature and back contact of relay 110 to ground on conductor 12/1 is open, and. therefore the advance of switch 150 is arrested.

A. circuit is now established for relay 216` of the allotted switching unit corresponding to the fifth group of operators positions. This circuit may be traced from battery, through the winding of relay 21S, conductor 11S, brush 103 of allotter 100, brush 153 of the group selector 150, the inner right arma ture and front contact of relay 110 to ground on conductor 124. Relay 21S, upon. energizing, locks over its inner left armature and contact to ground at the armature and back contact of relay 221, and at its outer right armature and front contact establishes a circuit for relay 219. rlhis circuit extends from battery, through the winding of relay 219, the armature and left contact of relay 220 to ground at the outer right armature and contact of relay 218. Relay 219 at its inner right armature establishes an obvious circuit for relay 220, which in turn locks over its left armature and front contact to ground at the outer right armature and front contact of relay 218. Relay 220 also closes two other circuits, one extending from ground through its outer right armature and front contact, the normally ciosed contacts of relay 223 to battery through the left winding .et relay and the vother S circuit fromv ground, thr-ough the inner right' armaturefand- 'front ycontact of relay 220,- over -conductor1f16g- .brush 102 of allotter 100,the inner-rightarmature and back contacttof relay-'125 to battery through the Winding of'relay 198.1 yRelay 108 energiZeS in this 'circuitifor 'Yapurpose .which Will be described hereinafter. The'ground poftential applied over conductora 116 also marks thev switchingunit which has-been taken for use asbusy to theallotter 100;:

Relay-222, upon energizing, locks over its right Winding and right armature, throughl the inner right armature and frontcon'tact of` relay 218, Lbrush 211fand the normal bank? terminal associated there-With to. ground at the outer right'armaturefand front contact of relay 218this lo'cklingcircuit'b'eingvmaintained until thebrush- 211 isf-stepped from its ynormal position, as hereinafter described; At :its left armature and front :contact relay 222 estab-lishes'an obvio'us'circuit through'y inner -left "armature: and front contact and n the outer right armaturegand front contact of relay 220.

Stepping A-magnet- 217 of= the pos'ition selector 200findividualltoithe fifth group; of

operators-positions, yupon energizing- .finf thel` previously tr-aced circuit finterrupts itsfoWni circuit and advances ,the brusheszo-f `the po; sition selector`I only'jl oneof Whiclrzbrushes is disclosed 'h'erein,y in Vthe idirectionE indicated* by the'farrow.Y Asfth'e-'brushesfof the*V switch advance the testf'brushf211 tests thecondi tion ofthe. suc-cessiveoperators positionsof the fifth ygroup'of positions.Jv Theterminals with whichv brushv211 cooperates, represent "ing non-calling; positions,i will presenta ground potential to brush-1211,such ground potential being-v applied-ffromfz'thel normal contacts of''pos'ition" relays similar to relay 252. This ground potential serves to maintaiirthe-hol'ding circuit= of relay 222 as abovetraced. Vhenf, however, the/'brushI 211 reaches thefirst position termina-lv rep: resent-ing the f first operators' position, no

ground potential willibefoundfthereon due to the`l energized condition of relay: 252, hence thc circuit 'of frelay-'222 is i openedand this relay becomes deenergized, Joper'iifng 1inturni the Voperatingcircuitof steppingmag' net '217, whereby'v the `Vswitch'l 2004 'cornes to rest;y Immediately.y that relay 222I releases its armatures,r a'-circuitisaclosedofrom bata tery through 'thecrigli't Winding-0f relay255, the right:armaturewand front'contact of re lay. 252, conductor I25.0.5 brush 211,contacts ofrelay 218, the right armature and backcontact o-f relay 222, the outer right armature and front contact of relay 219, to ground at the outer left armature and front .contact of relay 228. Relay 255 closes a locking circuit for itself and at its outer left armature disconnects battery from conductor 122 and theb-alancing coil 118. The selected operators position is maintained busy to other position selectors by ground potential 'applied over the brush 211I from the outer left armature and front contact of relay 228.

After the 'operator has completed the setting up of the desiredV line designation upon her keyboard (not shown), relay 219 becomes 'unlocked and opens the holding circuit of relays 252 and 258, Which :thereupon deenergizes. This holding circuit of relays 252 and 258 maybe traced from battery through the armature and contact of relay 251i-, left windings offre'lays 258^and 252,

fron't'contacts'of relay 252, co-nductor 250,V

brush 211; contacts of relay 218, right armature and 'back contacty of relay 222, the outer right armature and front contactof relay 219 to ground at the outer left armature and front contactofrelay 228. its outer lcft armature an'dbacl contact relay 219 also establishes' a circuit for relay 222'extending through the left Winding of this relay, the outer left armaturean'd back contact of relay 219,'.the inner right armature vand front contact of relay 218,- brush 211, conductor 250', togrou'nd at'the norm'a-l contact of the right'armature of relay 252. Relay 222, on energizing, locks 4over its right Winding and right armature", thence overthe circuit just ytraced to ground at the armature Contact of relay'252. With relay222energized, the previously traced circuit is established' forthe vstepping magnet 217, which lmagnet immediately "opens its oW'n circuit', stepping the brushes of the switch 200 forwardly from terminal to term-inal. Relay 222 is maintained energized'- in" each position of switchv 200 by ground potential on the terminal with which brush 211 cooperates extended from the nor mal right hand'contacts ofrelays similar to 252 at non-calling operators positions. hen the switch 200 reaches the next to its normal position, a circuit is closed from battery, through the right Winding of v'relay 222, right front contact of said relay, front contacts of the inner right armature ofrelay 218, brush-211, Winding of relayv 221'to ground. Relay v221 opens the 'holding circuit of relayf218, which relay becomes deenergized and opensthe circuit of relay 220. Relay 218 on deen'ergizingcompletes 4a cir-` cuit'fronr battery, through theI Winding and contact of'magnet' 217,' innen right armature'vr andY Aback-contact ofrelay 218, brush 211,0ute1 riglit-'ar-Inai'iure and back contact AtA of relay 220 to ground Stepping magnet 217 interrupts its own circuit once more and advances the brushes of switch 200 to their normal position terminals. Following the deenergization of relay 220, relay 223 is un-B locked and relay 222 releases its armatures. The other apparatus of the operators position and the apparatus of the switching unit which has been employed are restored to normal as soon as theirI functions have been completed Ain the manner fully set forth in the aforesaid application.

At the time relay 218 energized, battery potential was connected over conductor 232, the outer left arn'iature and front Contact of relay 218, conductor 117, to a point between the upper coil 113 and the windings of polarized relay 115, balancing' the polarized relay and causing its deenergization. The initial energizing circuit of relay 110 is now opened, but relay 110 is maintained locked over its locking winding until relay 108 energizes, which occurred, as previously described, upon the energization of relay 220. Upon the energization of relay 108 a circuit is established for the steppingmagnet 101 of the allotter 100 for the purpose A, of advancing the brushes 102 to 107, inclusive, of the allotter to allot a new switching unit for the use of the next calling operator. The circuit of magnet 101 may be traced from battery through the winding and armature contact of the magnet, the inner right armature and front contact of relay 108, the inner right armature and back contact of relay 125, brush 102, conductor 110 to ground at the inner right armature and front contact of relay 220 of the switching unitI employed by the operator of group 5, as previously described. Magnet 101 energizes interrupting its own circuit and advancing the brushes of the allotter one step. If the next switching unit is busy, ground potential is encountered by the brush 102 and the stepping magnet 101 of the allotter again energizes, advancing the brushes of the allotter a second step. This continues until the brush 102 encounters the test terminal of an idle switching unit, when the brushes of the allotter are arrested and brushes 103 to 107, inclusive, associate conductors leading` to the group relays `corresponding' to relays 208, and 218 of such allotted switching unit with the brushes 158 to 157 of the group selector 150.

1f calls in different groups are initiated simultaneously, for example, calls in the first and fifth groups of positions, the polarized relays 114 and 115 of such groups will both energize and cause the locking up of corresponding relays 109 and 110. lVhen, therefore, the group selector 150 is started, for example, from the position in which it is shown standing, the calling position in the first group will be given preference in the use of the allotted switching unit since the brush 152 will encounter terminal 158 first and operate the position selector start relay 208 of the first group. As soon as the switching unit becomes assigned to the use of the operator in the lirst group, the group selector 150 will again advance under the control of relays 115 and 110 and cause the operation of the start relay 218 of another allotted switching unit, in the manner previously described. Thus the group of positions first found by the group selector 150 becomes the first served and since each group of positions has four appearances in the banks of switch 150, each group of operators is therefore given equal preference in the use of allotted switching units, that is, the same number of switching units are available for the use of each of the ive groups of operators positions. The use of the group selector precludes the possibility of any one group of operators positions (20 positions) monopolizing all of the available allotted `vitching units, for each group of operators positions cannot appropriate to its own use at one time more than four allotted switching units.

1f an undue delay occurs in the allotment of a new switching unit, provision is made for causing the operation of the allotter 100 without awaiting the operation of relay 108. rlfhis is aeconiplished in the following manner: Upon the energization of any of the relays 109, 110, etc., a circuit is established from ground, through the interrupter 128, the outer right armature and front Contact of one of the relays 109, 110, etc., the right armature and back contact of relay 126, winding of relay 127 to battery at the inner left armature and back contact of relay 108. Relay 127, upon energizing, locks itself up in series with relay 126 from battery, through the inner left armature of relay 108, windings of relays 127 and 126 to ground at the armature contact of relay 127. Relay 126 energizes in this locking circuit as soon as the interrupter 128 reaches a noncircuit closing position. l/Vith relay 126 energized as soon as the interrupter 128 again reaches a circuit closing position, a circuit is established through the left armature and contact of relay 126, through the winding of relay 125 to battery. Relay 125, upon energizing, closes a circuit from battery, through the winding of stepping magnet 101, to ground through the outer right armature and Contact of relay 125, this circuit being maintained until the interrupter 128 reaches the next non-circuit closing position, when relay 125 deenergizes, in turn causing the deenergization of stepping magnet 101 and the advance of the brushes of the allotter one step. Relay 125 also closes a circuit for relay 108 extending from battery, through l.the winding of relay 108, the

inner armatures and front contacts of relay 125, the left armature and contact of relay 126 to ground through the interrupter 128.

Relay 108, upon energizing, opens the holding circuit of relays 126 and 127, whereupon these relays deenergize. Relay 126 upon deenergizing, opens the previously traced circuit of relay 125 preventing the reenergization of relay 125 when the interrupter 128 again reaches a circuit closing position. With relay 125 deenergizedand relay 108 energized, a holding circuit is established for relay 108 extending through its winding, the inner right armature and back contact of relay 125 to the brush 102 of the allotter, this holding circuit being maintained as long as the brush 102 engages test terminals of busy switching units. As long as the relay 108 is maintained energized, the circuit of stepping magnet 101 is maintained as previously described to advance the brushes of the allotter in search of an idle switching unit.

That is claimed is:

1. In a telephone system, a plurality of groups of operators positions, a plurality of switching units, means for allot-ting a switching unit for the use of any operator, and means for giving each group of operators positions equal preference in the use of allotted switching units. A

2. In a telephone system, a plurality of groups of operators positions, a. plurality of switching units, means for allotting a switching unit for the use of any operator, and a group selector for selecting the group of positions in which a calling operator is located and for associating such group of positions with an allotted switching unit, said group selector being arranged to give each group of operators positions equal preference in the use of allotted switching units.

3. In a telephone system, a plurality of groups of operators positions, a plurality of switching units, each including as many position selector switches as there are groups of positions, means for allotting a switching unit for the use of any operator, and means operative upon the initiation of a call by any operator to select the group in whichI the calling position is located and to start a position selector to associate the calling position with an allotted switching unit.

4. In a telephone system, a plurality of groups of operators positions, a plurality of switching units, each including as many position selector switches as there are groups of positions, means for allotting a switching unit for the use of any operator, and a group selector switch operative upon the initiation of a call by any operator to select the group in which the calling position is located and to start a position selector to associate the calling position with an allotted switching unit.

5. In a telephone system, a plurality of groups of operators positions, a plurality of switching units, means for allotting a switching unit for the use of any operator, a group selector, test leads from each of said groups of positions terminating in rotation and each with a plurality of appearances in the bank of said selector, and means under the control of any operator for st-arting said selector to associate the group of positions in which said operators position is located with an allotted switching unit.

6. In a telephone system, a plurality of groups of operatorspositions, a plurality of switching units, means for allotting a switching unit for the use of any operator, means for associating an allotted switching unit with an operators position of any of said groups, means effective thereafter for operating said allotting means to allot another switching unit for use, and means automatically effective after the eiapse of a definite time interval for operating said allotting means in the event of a delay in associating the calling operators position with an allotted switching unit.

7. In a telephone system, a plurality of groups of operators positions, a plurality of switching units, means for allotting a switching unit for the use of any operator, a group selectorfor selecting the group of positions in which a calling operator is located and for associating such group of positions with an allotted switching unit, means effective thereafter for operating said allotting means to allot another switching unit for use, and means automatically effective after the elapse of a definite time interval for operating said allotting means in the event of a delay in associating a calling operators position with an allotted switching unit.

In witness whereof, I hereunto subscribe my name this 27th day of June A. D., 1923.

ROBERT W. HARPER. 

